At some point all aquarists have kept a goldfish.  It might have been a prize at the local carnival, or a birthday party gift, or even a mother’s day present, but a goldfish in a bowl is a familiar sight to most.  This month I would like to briefly delve into the husbandry and care of the goldfish.

Goldfish are members of the fish family Cyprindae.  They share this distinction with many thousands of other fish, like the Barbs, Danios, Red Tail Shark, Rasboras, and more.  The scientific name of the goldfish is Carassius auratus.  The name Carassius refers to many of the Carp family, and the auratus literally means ‘overlaid with gold’.  Along with Koi and pond carp, goldfish make up a large portion of this group of fish.

Goldfish come in many shapes and sizes.  The ‘common’ goldfish more closely resembles the many species of carp found in ponds and lakes all over the world.  Goldfish originally derived from temperate Asia, but have been introduced to all parts of the world.  Many cultures began to ‘domesticate’ the goldfish, as long as 1300 years ago. They selected for a variety of genetic traits, like color, fin shape, and body shape.  The result of this selective breeding allows the myriad of goldfish types available to us as hobbyists today.  The typical common goldfish, also sold as feeder fish a many petstores, appears much as its wild natural great grandfather would have appeared in Asia.  However, all the fancy variations, veil-tails, bubble-eyes, orandas, etc. are all strains developed through selective breeding, and do not occur in nature in that form naturally.

Because goldfish are temperate animals, they can withstand a wide range of temperatures.  In a natural pond, or a water garden large enough, goldfish may even winter over when the water freezes at the surface.  In the aquarium- it’s best to maintain them at 68 to 76 degrees F.  Because of their metabolic demands, the cooler water is best for their survival.

Goldfish are natural born pigs.  They are messy.  And they eat a lot.  Thus creating the biggest obstacle for many goldfish keepers- the water quality.  Like most fish, goldfish prefer to live in clean water.  They can tolerate a wide range of pH, but prefer neutral to slightly basic water.  They do not do well in any aquarium with ammonia or nitrite present.  Since they can easily produce huge quantities of wastes, and ammonia, they should be kept in well-filtered aquariums.  That’s right- filtered aquariums.  Problem is most people try them in a very small bowl first.

Unfortunately- this first experience for many with fish in general tends to be a poor one.  Setting up a goldfish in a 1-gallon bowl is a recipe for disaster.  As I mentioned, they eat a lot.  They also produce a lot of wastes.  So, in this small container, they will accumulate very high concentrations of the chemicals most toxic to them.  You could do daily water changes, but this can be stressful to the fish.  So, it’s best to house the goldfish in a filtered aquarium.

Since goldfish are so messy, and will grow rather large- its best to house only 1 small fish per ten gallons.  As they get larger- each fish could easily take up 30 gallons each!  This and the fact they tend to root around the gravel and disrupt plants and rock work, and the fact they like cooler temperatures, makes them less than ideal for the community aquarium. I general, goldfish are peaceful fish and will get along well with a variety of other species, but they have different needs than most other fish and most likely will never thrive in the community aquarium.

The last point I want to bring up is feeding and nutrition.  Goldfish in nature are opportunists.  Many thousands of years have developed this vegetation loving fish into an opportunistic feeder.  So, whenever a goldfish is confronted with food, its instinctive reaction is to eat it.  Most foods available to day have a very high protein component. This is quite different from the mostly fiber diet they consume in nature.  They eat mostly algaes, and grasses and aquatic plants in the wild.  So, we have to be careful how much ‘high protein’ food they consume in our aquarium.  The other inherent problem is overfeeding.  As I said, goldfish will always eat when presented with food.  This of course is their downfall, as they always appear to be hungry.  Too many aquarists have killed their goldfish with kindness trying to appease that bottomless appetite.  Unfortunately- it is quite possible for that fish to eat itself to death.  To literally tear its intestines, or create a backlog of digestion leading to death.  So the simple solution is to monitor feeding.  I recommend one to two pellets per fish, once per day.  This may sound barbaric, but keep in mind that these fish live in a relatively small space.  There are no predators waiting to eat them, no currents to battle.  Their water quality is stable (we hope) and they have relatively little to do.  So their caloric needs are very reduced.  And that 1 to 2 pellets will be more than enough to have them grow and survive in your aquarium.

Goldfish really do make wonderful pets, but keep in mind their requirements differ greatly from that provided by just a bowl.  Many people keep a variety of goldfish for many many years.  They can easily live into their teens, and some of the fancy goldfish can live twice that long.  So the next time you decide to pick out a cute little goldfish, consider the time it will be in your life, and its ultimate size, and set up a beautiful tank for golds!